Corrosion-resistant, mechanically workable alloy



Patented July 2, 1935 UNITED STATES PATENT OFFICE- 2,006,601 CORROSION-RESISTANT, MECHANICALLY WQRKABLE ALL Miiller and Moritz Niessner,

Wolf Johannes No Drawing.

Serial No.

5 Claims.

This invention relates to alloys adapted to be used in the production of articles which have to fulfill the requirements of being resistant to corrosion and capable of being mechanically worked, such as for example, boiling vessels and castings such as fittings (valves and the like) and so forth. The present invention constitutes a continuation in part of our invention disclosed and claimed in our co-pending application, Serial No. 678,473, filed June 30, 1933.

It is known from the literature that gamma brass, that is to say 'copper-zinc-alloys containing from 31 to 40% of copper, is more resistant to corrosion than the brass alloys usually employed which belong to the alpha and alpha beta fields and contain for example, 68 to 72% of copper. It is, however, impossible to employ the gamma allows industrially ona technical scale because said alloysare extraordinarily hard 'and brittle and are consequently unworkable.

It has now however,-been unexpectedly ascertained, that copper ifnc-faplmgs of the beta gamma field, i. e. copper;zin -alloys containing about 40 to of copper, constitute a corrosion resistant structural material for machines and machine parts which is at the same time mechanically workable and by virtue of these properties, suitable for the manufacture of articles which are required to resist corrosion but must nevertheless undergo a mechanical working.

An example of an alloy fulfilling these requirements is one containing 44% of copper and 56% of zinc. The copper content of these binary alloys should preferably not fall below 43%.

The invention is based on the fact that the workability of such alloys can be increased by adding thereto small quantities of cobalt and nickel jointly, the joint quantities of such added metals amounting to from two to ten per cent.

Particularly useful are alloys according to the Application February 27, 1935, 8,487. In Austria July 8, 1932 invention which comprise an addition of 1 to 6 per cent of cobalt and 2 to 8 per cent of nickel the amounts of such added metals jointly being less than 10% and preferably less than 6%.

When adding cobalt and nickel to the said al- 45.0% of copper, 2.0% of nickel, 2.5% of cobalt,

Remainder zinc.

What we claim is:

1. Corrosion-resistant, mechanically workable alloys which consist substantially of a copper- Zinc alloy containing copper in an amount corresponding to beta gamma-brass and an addition of from two to ten per cent. of the elements nickel and cobalt jointly.

2. Corrosion-resistant, mechanically workable alloys according to claim 1, containing from 1 to 6 per cent of cobalt.

3. Corrosion-resistant, mechanically workable alloys according to claim 1, containing from 2 to 8 per cent of nickel.

4. Corrosion-resistant, mechanically workable alloys according to claim 1, wherein the zinc is present in an amount above 50 per cent.

5. A corrosion-resistant and mechanically workable alloy having the following composition: 45 per cent. copper, 2 per cent. nickel, 2.5 per cent. cobalt, remainder zinc.

WOLF JOHANNES MiiLLER. MoRrrz NIESSNER. 

